Combination strike and strike box



Oct. 13, 1964 E. L. SCHLAGE COMBINATION swam: AND STRIKE BOX Filed April 18, 1963 FIG./

- INVENTOR.

ERNEST L. SCHLAGE ATTORNEY United States Patent This invention relates to latch strikes and more particularly to a combination strike and strike box of the borein type wherein the strike box is received in a bore opening outwardly of the face of the jamb that is at right angles to the-plane of the door.

' Av considerable amount of labor may be saved in the installation of latch strikes by employing. the surface mounted type wherein the strike plate is secured against the face of the jamb without sinking said plate in a mortise in the jamb. This procedure requires a fairly thin strike plate because of the limited clearance between the jamb and the adjacent edge of the door. However, the plate can be stiffened and, at the same time, the appearance of the strike enhanced, by providing a strike box formed integrally with the strike plate.

Additional labor may be saved by boring a hole in the face of the jarnb for receiving the box therein. However, providing a means for securementof the strike to the jamb has presented a problem, especially if it is desired to eliminate the screw holes in the strike plate which have heretofore been employed to secure the strike plate to the 'amb. 1 One method employed has been to limit the depth of the bore and provide screws through the bottom of the strike box and threadedly engaging the bottom of the bore so that when the screws are tightened the box is pulled into the, bore with the back face of the strike plate abutting the face of the jamb or, if the jamb is mortised, with the back face of the strike plate abutting the bottom of the mortise. Although this procedure provides an adequate securement it calls for care in limiting the depth of the bore to insure that suffici'ent wood is left to receive the screw. Furthermore, the appearance of the box is marred by the conspicuous screw heads thus detracting from the neat appearance which a strike box is designed to effect.

The main object of the present invention is the provision of an improved combination strike and strike box which eliminates many of thevdisadvantages of prior art devices of like nature.

Another object of the invention is the provision of a combination strike and strike box which may be installed on a door jamb with a minimum amount of labor and skill.

Still another object of the invention is the provision of a combination strike and strike box lending itself to surface mounting and presenting a neat appearance.

Yet another object of the invention is the provision of a strike construction wherein an extremely reliable installation maybe effected by means of only one fastening screw.

Another object of the invention is the provision of a latch strike which may be recessed in a mortise formed with straight sides which may be formed by use of a chisel having a straight cutting edge.

Other objects and advantages of the invention will be apparent from the following specification and drawing wherein:

FIG. 1 is a perspective of a preferred form of combi strike as taken in a plane indicated by lines 3--3 of FIG. 2.

In detail, and first with reference to FIG. 1 the invention comprises a strike plate, generally designated 1 to which a strike box 2 is integrally secured.

The strike plate 1 comprises a generally flat plate of sheet material bent at the marginal portion adjacentone edge 3 to provide a camming surface 4 which is adapted to engage the latchbolt (not shown) and retract the same as the door is closed.

The plate 1 is generally trapezoidal in shape having a vertically extending inner edge 5 opposite edge 3 and a pair of upper and lower edges 6, 7 which converge toward edge 3 at an included angle of about The strike box 2 is formed integrally with the plate 1, preferably by a drawing process, and includes a bottom wall in, and upper and lower walls 11, 12. A front wall 13 is formed generally perpendicular to plate 1 and the flat side of the latchbolt is adapted to lie alongside said front wall when the door is closed and said latchbolt is projected into the strike box 2.

Opposite front wall 13 is a rear wall 14 that is slantingly disposed relative to plate 1 and extends from a generally circular juncture 15 (FIG. 3) with plate 1 to a generally straight juncture 16 with the bottom 16.

Upper and lower walls ll, 12 and rear Wall 14 merge with each'other and with plate 1 so as to provide a substantially circular juncture with plate 1 for more than plate 1.

. Since the remainder of the juncture between the box and the plate is substantially straight at front wall 13 the opening in strike plate 10 is generally D-shaped. Such a shape substantially corresponds to the cross sectional shape of a conventional latchbolt.

Referrin gto FIG. 1 the combination strike and strike box is adapted to be installed on a door jamb 26 provided with a bore 21 which may be bored into the jamb from the face 22 of the jamb that is at right angles to the plane of the door when the latter is closed. In FIG.. 3 a door step 23 is indicated against which the door engages when it is slammed. V

The radius of bore 21 (FIG. 2) is substantially equal to the radius of the circular juncture that connects the walls 11, 12 and 14 with the strike plate 1. Since said juncture extends for more than a semicircle, it is seen that the box is automatically centered in the bore despite the fact that there is clearance between the flat front sidewall 13 of the box and the adjacent sidewall of the bore.

For the purpose of securing the strike and box to the jamb 26 a screw hole 25 for screw 27 is provided in the rear slanting wall 14 at a point closely adjacent thejuncture 16 between said wall 14- and bottom It). A frustoconical seat 26 is formed around hole 25 by striking out an annular flange as best seen in FIG. 3.

From FIG. 3 it will be apparent that a hole for starting screw 27 may readily be formed by inserting a nail' or the like through hole 25 disposed perpendicular to wall 14 and allowing sufficient clearance for the bit of a screwdriver inserted through the open side of the strike box 2.

By tightening screw 27 it will be apparent that the strike box will be drawn into bore 21 and the face plate 1 will be urged into abutment with the face 22 of the jamb 24). It is important that the screw hole 25 be placed closely adjacent bottom it in order to develop a maximum lever arm for slightly rotating the plate 1 about the juncture 15 between rear wall 14 and face In this connection it will be seen from FIG. 2 that almost the entire plate is, in effect, rotated about a point very closely adjacent the inner vertical edge 5 of the strike plate 1 thus provding a very tight abutment between the plate and the face 22 of the jamb.

Since the distance between the juncture 15 and the vertical edge 5 of the plate is very small the amount that said edge 5 tends to swing outwardly from the face of the door is negligible. Furthermore, said edge 5 is pulled into the face of the jamb by the component of the force of the screw that is axially of the bore 21.

At this point it will be noted that if the strike plate were circular with its outer periphery concentric with the axis of bore 21, as in some prior art strike plates, an inordinately wide flange would result which Would interfere with stop 23 in many instances when the door is thin.

Another important advantage accruing from the above described shape of strike plate 1 is the improved resistance of the structure to being pulled outwardly in a direction away from stop 23. In this connection it should be noted that, when the door is slammed, the forces applied to the strike are not very great when the door is closing but are exceedingly large when the door rebounds olf the stop 23. It is in thisllatter situation that the flat face of the latchbolt abuts the flat front sidewall 13 of the strike box and tends to pull the entire structure outwardly of the jamb.

It will be noted from FIG. 2 that the converging upper and lower edges 6, 7 of the strike plate tend to wedge into the wood of the jamb thus adding greatly to the resistance to failure when the above mentioned rebound force is applied. It is true, of course, that this advantage obtains to a greater degree if the strike plate is sunk into a mortise in the jamb, and the present invention contemplates this type of installation. However, the efiect of tightening screw 27, as described above, causes the upper and lower edges 6, 7 to be embedded slightly into the face 22 of jamb 20 so that the strengthening effect of the trapezoidal shape still obtains.

It will be apparent that the above described structure provides an extremely strong installation by means of only one fastening element. The installed structure also has an extremely neat appearance and the head of screw 27 does not detract from the smooth interior of the strike box 2. Furthermore, when it is desired to recess the strike plate wthin a mortise, such mortise may readily be formed by means of a conventional chisel having a straight cutting edge.

I claim:

A combination strike and strike box adapted to be applied to a surface of a door jamb provided with an outwardly opening bore comprising:

a strike plate adapted to be applied against said surface,

a strike box integral with said plate and adapted to be received in said bore, said box being formed with a sidewall generally perpendicular to said plate and adapted to engage a side of the latch bolt of a door on said jamb when said door is closed,

a sidewall on said box opposite said perpendicular sidewall and slantingly disposed relative to said plate,

said slanting sidewall being provided with a screw hole for receiving a screw therethrough adapted to threadedly engage the sidewall of said bore whereby when said screw is tightened said plate is urged against said face,

said strike plate being generally trapezoidal in shape having opposite outer and inner edges and upper and lower edges, said upper and lower edges converging toward said outer edge, whereby said plate is slightly imbedded in said surface when said screw is tightened, and whereby said converging edges resist outward movement of said strike plate upon the imposition of rebound forces on said box and plate.

Samuelson Aug. 22, 1911 Fendring Feb. 10, 1942 

